Toei Animation announced that more than one background musics of Dragon Ball Kai were suspected to infringe the copyrights of third parties. They have already replaced those musics with the original BGMs of Dragon Ball Z.
Toei Animation had assigned the music of Dragon Ball Kai to Yamamoto Kenji instead of Kikuchi Shunsuke. Yamamoto Kenji's other musics have also been suspected to be plagiarized works. (ref. niconico video)
This was unexpected... well you cant perceive human factor with 100% accuracy, guess that there are fools like this. They at least make us enjoy life more, when it comes to enjoying different personalities of people, that is.
I thought that every anime soundtrack was stolen from paying homage to another work. Usually composers are not paid generously and have tight deadlines for creating music.... which is often why you hear parts of classical works (whose copyrights have expired) or blatant style/melody imitations of other artists. Even most of the truly original artists tend to mimic the same "sound" as their previous works with variation in melody. It's safer and more profitable.
At least 95% of the music you hear is heavily influenced by or plagiarized from another work.... since actual originality puts so much pressure on time and budget. I'm not saying that's an excuse, but that immense pressure tends to lead artists down the path of theft..... the same way a student with only a few hours to write a report might try to grab excerpts from wikipedia.
Wow, that's just sad... but personally, I love the fact that, instead of plagiarizing music from some obscure source (thus increasing the possibilities that he would get away with it), he was just like "Screw that, I am going to steal songs from Avatar and Terminator Salvation. Clearly, no one will notice it!"
"I know about people who talk about suffering for the common good. It's never bloody them! When you hear a man shouting "Forward, brave comrades!" you'll see he's the one behind the bloody big rock and the one wearing the only really arrow-proof helmet!"
-- Rincewind gives a speech on politics. (Terry Pratchett, Interesting Times)